What happens when you inject the brains of spirit mediums with radioactive tracers, and then watch their brains? Apparently, you see odd changes in brain behaviour. That's what happened when researchers took ten Brazilian mediums - half experienced, half not - and tracked their brain activity (or at least, regional cerebral blood flow [rCBF], which is closely correlated) using SPECT (Single Photon Emission Computed Tomography).

The researchers firstly did a control experiment, in which the mediums just did some normal writing, and then followed up with another scan while they were practicing 'psychography' - in which spirits allegedly write "through the medium's hand” while they are in a trance...